It is the purpose of this project to study the chemistry and structure of amyloid and amyloid related proteins. The main topics of present interest are: 1. Isolation and chemical characterization of amyloid fibril protein from various types of systemic amyloidosis and localized amyloid deposits. 2. Isolation and physical and chemical characterization of the paired helical filaments of the neurofibrillary tangles and the amyloid fibrils of the neuritic plaques and cerebral vessels in Alzheimer's disease.